Stent and therapeutic delivery system

ABSTRACT

Apparatus and a method for treating an irregularity in a wall of a vessel of a patient defined by an irregular or afflicted wall portion with adjacent normal wall portions comprises a catheter having a distal end portion for being guided through the vessel to the site of the irregularity. A balloon associated with said distal end portion of the catheter for selective inflating to contact the walls of the vessel urges a stent carried by the distal end portion of the catheter in a constricted condition for passage through the vessel into an expanded form with the stent spanning the afflicted wall portion and contacting the adjacent wall portions. The catheter is formed with lumens for inflating the balloon, for receiving a guidewire for guiding the catheter through the vessel, and for connecting a port in the catheter proximate the afflicted wall portion to enable delivery of a therapeutic agent into the vessel to contact the stent and the irregular wall portion.

This application is a continuation of application Ser. No. 08/268,999,filed Jun. 30, 1994 now U.S. Pat. No. 5,439,446.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to percutaneous therapy and moreparticularly relates to a method and system for percutaneoustransluminal delivery of a stent and therapeutic agent.

2. Description of Related Art

Physicians often use medical guidewires and catheters in combination.Medical guidewires are devices navigatable through narrow passages inthe body such as vessels, tubes, ducts, passages and the like,hereinafter collectively referred to as vessels. A physician controlsthe position and travel of a distal end of the guidewire by manipulatinga steering mechanism at a proximal end outside the body. In otherapplications the physician guides the catheter through a laparoscope orendoscope. Medical catheters generally comprise hollow, flexible tubesthat convey fluids, such as contrast, embolic, or pharmacologicalagents, to or from a vessel within a body.

Typically in transluminal procedures, a physician inserts and directs amedical guidewire through a vessel in a patient's body. The physicianmonitors the travel of the guidewire by a fluoroscope or other knowndevice. Once positioned proximate the desired area, a steering mechanismis removed from the guidewire and a medical catheter is inserted intothe vessel along the guidewire.

Oftentimes these catheters include specialized attachments for providingdifferent treatment modalities. For example, the following referencesdisclose catheters with attachments for administering a therapeuticagent and performing balloon therapy:

    ______________________________________                                                4,824,436                                                                             (1989) Wolinsky                                                       4,832,688                                                                             (1989) Sagae et al.                                                   5,254,089                                                                             (1993) Wang                                                           08/105,737                                                                            (1993) Lennox et al.                                          ______________________________________                                    

U.S. Pat. No. 4,824,436 to Wolinsky discloses a multi-lumen catheterhaving opposed ring balloons positionable on opposite sides of a plaqueformation in a blood vessel. Inflation of the ring balloons define anisolated volume in the vessel about the plaque. Heparin is then injectedinto the volume between the ring to assist the body in repairing theplaque deposit. This patent also discloses a central balloon which canbe employed to rupture the plaque prior to inflation of the ringballoon.

U.S. Pat. No. 4,832,688 to Sagae et al. discloses a multi-lumen catheterhaving an occlusion balloon positionable distally of a tear in a vesselwall. Inflating the balloon occludes the vessel and isolates at thetear. A therapeutic agent, such as heparin or thrombin, injected fromthe catheter into the volume reduces the risk of thrombosis orrestenosis. The balloon is then deflated and moved adjacent the ruptureand reinflated to repair the ruptured wall by coagulation of bloodthereat.

U.S. Pat. No. 5,254,089 discloses a balloon catheter having an array ofconduits disposed within the outer wall of the balloon. The conduitsinclude apertures in the other wall for delivery of medications throughthe wall of the balloon into the body of a patient. This type of balloonis often referred to as a channeled balloon.

U.S. application Ser. No. 08/105,737 to Lennox et al., disclosescatheters having spaced balloons for treating aneurysms. The inflatedballoons define an isolated volume about the aneurysm. A port connects avacuum source to evacuate the volume and draw the aneurysmal wall towardits ordinary position. Inflating a third balloon with a heated fluid tocontact the aneurysmal wall effects the repair.

Therapeutic agent and balloon delivery systems must meet certaincriteria. That is, the cross-sectional dimension of the catheter must beminimized to enable transit through the vessel while also havingsufficient dimension to enable fluid flow to selectively inflate anddeflate the balloon, guidewires to pass therein, and therapeutic agentsto flow therethrough for delivery along the catheter. Catheters mustalso have sufficient internal rigidity to prevent collapse of the lumenswhile having sufficient flexibility for passage along vessels.

The following references disclose stent delivery systems:

    ______________________________________                                                4,690,684                                                                            (1987) McGreevy et al.                                                 4,922,905                                                                            (1990) Strecker                                                        4,950,227                                                                            (1990) Savin et al.                                                    5,059,211                                                                            (1991) Stack et al.                                                    5,108,416                                                                            (1992) Ryan et al.                                                     5,158,548                                                                            (1992) Lau et al.                                                      5,234,457                                                                            (1993) Anderson                                                        5,242,399                                                                            (1993) Lau et al.                                              ______________________________________                                    

Stent delivery systems, as disclosed by the Lau et al. and Ryan et al.patents, often include a catheter supporting a compacted stent fortransport in a vessel and an expansible device for expanding the stentradially to implant the stent in the vessel wall. After removal of thecatheter, the expanded stent keeps the vessels from closing.

The McGreevy et al. patent discloses a stent formed of biologicallycompatible material, such a frozen blood plasma or the like. Accordingto McGreevy et al., a stent of this type carried by a catheter may beinserted into opposed ends of a ruptured vessel to support the separatedvessel walls while the ends are bonded together. Once deployed, the heatfrom the bonding operation and the body eventually melt the stent andclear the vessel.

The Strecker, patent describes a stent and delivery system. The stent isknitted from metal or plastic filaments and has a tubular structure. Thedelivery system includes a balloon catheter and a coaxial sheath. Thecatheter supports and carries the compacted stent to a site within thebody. The sheath covers the stent preventing premature deployment andfacilitating transit of the stent through passages in the body. Exposureof the stent by moving the sheath axially with respect to the catheterand expansion of a balloon urges the stent into contact with the wallsof the vessel. Deflation of the balloon frees it from the stent andenables withdrawal from the vessel of the delivery system.

In the Savin et al. patent a stent delivery system includes a catheterhaving an expansible distal portion, a stent carried thereon in acontracted position for expansion thereby and sleeves that overlie theend portions of the stent. The sleeves protect the vessel and the stentduring transit without substantially inhibiting deployment of the stent.

The Stack et al. patent discloses a stent delivery system comprising acatheter for delivering a compressed stent on a balloon or mechanicalextension to the locus of a stenotic lesion. The balloon or mechanicalextension proximate the distal end expands the stent and deflation ofthe balloon or retraction of the mechanical extension permits withdrawalof the distal end of the catheter through the stent. The stent comprisesbioabsorbable porous material that reduces the likelihood ofembolization and promotes tissue ingrowth in order to encapsulate thestent.

In accordance with the Anderson patent a stent delivery system includesa dissolvable material that impregnates a self-expanding stent in acompacted form. In one embodiment the removal of a sheath exposes thestent to body heat and liquids so that the material dissolves and thestent expands into a deployed position.

Stent delivery systems used in such procedures generally includecatheters with selectively expansible devices to deliver and expand acontracted "stent" or restraints that can be removed to allow aself-expanding stent to assure an enlarged or expanded configuration.Stents are known and have a variety of forms and applications. Forexample, stents serve as prostheses and graft carriers in percutaneousangioplasty. Stents used as an endoprothesis and graft carriers to whichthe present invention relates usually comprise radially expansibletubular structures for implant into the tissue surrounding "vessels" tomaintain their patency. As is known, such stents are utilized in bodycanals, blood vessels, ducts and other body passages, and the term"vessel" is meant to include all such passages.

Like the previously described therapeutic agent and balloon therapysystems, stent delivery systems must conform to several importantcriteria. First, it is important to minimize the transverse dimension ofthe delivery system, so the stent must be capable of compaction againsta delivery device, such as a catheter. Second, the delivery system mustfacilitate the deployment of the stent once located in a vessel. Third,the stent delivery system must easily disengage from the stent after thestent is deployed. Fourth, the procedure for removing the deliverysystem from the body must be straightforward. Fifth, the delivery systemmust operate reliably.

It has been found that the administration of therapeutic agents with astent can reduce the risks of thrombosis or stenosis associated withstents. Stents administered along with seed cells, such as endothelialcells derived from adipose tissue, can accelerate the reformation of anafflicted area. Likewise, tears or other vessel damage associated withballoon angioplasty can be reduced by a deployed stent used incombination with a therapeutic agent.

When both therapeutic agent and stent therapies are required, aphysician generally (1) steers a guidewire to the treatment locus, (2)guides a catheter over the guidewire, (3) operates the catheter toprovide the first stage of treatment, (4) inserts an exchange guidewireto the guidewire, (5) withdraws the catheter, (6) guides a secondcatheter over the guidewire, and (7) operates the second catheter toprovide the second stage of treatment. After this, the physicianwithdraws the guidewire, if not previously removed, and the catheterfrom the body of the patient.

Although percutaneous transluminal procedures have improved in recentyears, it is still a fact that each insertion and extraction risksfurther damage to afflicted areas and damage to otherwise unaffectedareas through which the instruments pass and can add to patient trauma.Moreover, insertion and withdrawal of additional instruments in sequenceincreases the time of the physician, staff, and medical facility, andthe cost of multiple instruments. Thus, procedures and devices reducingthe number of instruments necessarily inserted and withdrawn from apatient are generally preferred.

Thus, the above-described references generally disclose various forms oftreatments or therapies using a balloon catheter in percutaneoustransluminal procedures. Some combined with stent delivery systems,which may include a balloon for deploying the stent, while otherscombine balloon therapy and therapeutic agent delivery systems. However,none of these references disclose a delivery system having asufficiently small cross section and flexibility for use within apatient's vessel while also providing sufficiently large cross sectionand strength to permit delivery of therapeutic agent and stenttherapies. None provides a structure for improving the efficiency ofpercutaneous transluminal procedures by providing a combined stent andtherapeutic agent delivery system. None disclose a delivery system andmethod capable of delivering a therapeutic agent upstream from a stentdeployed by the system along an afflicted wall of an occluded vessel sothat the agent contacts the stent and afflicted wall. Furthermore, noneof these references disclose a system for delivery of encapsulatedtherapeutic agents which bond to the afflicted area and/or stentdeployed by the system to provide continued therapeutic efficacy afterwithdrawal of the system.

SUMMARY

Therefore, it is an object of this invention to provide a method andapparatus for percutaneous stent and therapeutic agent treatments atirregularities in a vessel of a patient including aneurysms, stenosis,ruptures, thrombosis, malignant and benign tumors and growths and otherlike vessel irregularities.

It is another object of this invention to provide a stent andtherapeutic agent delivery system adapted for passage through thevessels of a patient while providing a sufficient platform for stent andtherapeutic agent modality treatments.

Yet another object of this invention is to provide a method andapparatus which reduces the steps and time necessary to deliver a stentand therapeutic agent to an afflicted portion of a vessel in a patient.

It is a further object of this invention to provide a method andapparatus for delivering a stent and therapeutic agent to a vessel whichis relatively simple and inexpensive to produce and use.

In accordance with one aspect of this invention an apparatus fortreating an irregularity in a vessel wall includes a catheter for beingguided through the vessel to the site of an irregularity withan-expansible balloon at its distal end. The balloon inflates to contactthe walls of the vessel and occlude the vessel. A port in the catheterdelivers a therapeutic agent that then can contact the stent means inits expanded form.

According to another aspect of this invention, a method for treating anirregularity in a vessel wall includes the steps of positioning a distalend of a catheter proximate the irregularity, inflating a balloonoperatively associated with the catheter to occlude the vessel anddeploying a stent mounted on the balloon so as to span the irregularity.The treatment further includes introducing a therapeutic agent tocontact the deployed stent and deflating the balloon reopens the vesselto enable withdrawal of the catheter and balloon and the flow of liquidthrough the vessel.

A further aspect of this invention comprises a delivery system fordelivering a stent and therapeutic agent to treat a vessel wallirregularity. The system includes a catheter guided through the vesselproximate the irregularity, a stent carried by the balloon fordeployment in an expanded condition. The catheter includes an inflationlumen for enabling the balloon to expand and occlude the vessel. Adelivery lumen exits the catheter at a delivery port position proximalthe balloon for delivering a therapeutic agent to the occluded vessel inorder to contact the stent.

BRIEF DESCRIPTION OF THE DRAWINGS

The appended claims particularly point out and distinctly claim thesubject matter of this invention. The various objects, advantages andnovel features of this invention will be more fully apparent from areading of the following detailed description in conjunction with theaccompanying drawings in which like reference numerals refer to likeparts, and in which:

FIG. 1 depicts a single passage vessel with an irregularity comprising atear in the wall of the vessel;

FIG. 2 depicts in side elevation an embodiment of a delivery systemconstructed in accordance with this invention for treating theirregularity in the vessel of FIG. 1 at a first stage in a treatmentmodality;

FIG. 3 is a view, partly in schematic and partly in perspective form, ofportions of the delivery system taken along lines 3--3 in FIG. 2;

FIG. 4 depicts the delivery system of FIG. 2 at an intermediate stage ofthe treatment modality;

FIG. 5 depicts a repair vessel and the delivery system of FIG. 2 atfinal stage of the treatment modality prior to its removal from thevessel;

FIG. 6 depicts in side elevation another embodiment of a delivery systemsimilar to FIG. 2 for treating an irregularity the vessel of FIG. 1;

FIG. 7 is a view, partly in schematic and partly in perspective form, ofportions of the delivery system of FIG. 6 taken along lines 7--7 in FIG.6;

FIG. 8 depicts in side elevation the embodiment of FIG. 6 at a firststage in a treatment modality;

FIG. 9 depicts in side elevation the embodiment of FIG. 6 at anintermediate stage in the treatment modality;

FIG. 10 depicts in side elevation the embodiment of FIG. 6 at a finalstage of the treatment modality;

FIG. 11 depicts another embodiment of the delivery system of the presentinvention, similar to those of FIGS. 2 and 6, in the at a first stage ina treatment modality for treating an irregularity in the vessel of FIG.1;

FIG. 12 is a view, partly in schematic and partly in perspective form,of portions of the delivery system of FIG. 11 taken along lines 12--12in FIG. 11;

FIG. 13 depicts in side elevation the embodiment of FIG. 11 at a firststage in a treatment modality;

FIG. 14 depicts in side elevation the embodiment of FIG. 11 at anintermediate stage in the treatment modality;

FIG. 15 depicts in side elevation the embodiment of FIG. 11 at a finalstage of the treatment modality; and

FIG. 16 depicts in side elevation an alternative balloon mounted on acatheter for use in the embodiments of the present invention.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

FIG. 1 depicts, in simplified form, a single-passage, tubular vessel 20through tissue 21, such as peri-arterial tissue, defined by a vesselwall 22. Although FIG. 1, and the other similar figures, depict a vesselwall as comprising a single homogeneous layer, it will be recognizedthat an actual vessel wall has multiple layers. However, this inventioncan be understood by referring to the simplified, homogenousrepresentation in the figures.

FIG. 1 illustrates an irregularity or abnormality in the wall of thevessel 20 at an afflicted or irregular wall portion 23 in the vesselwall 22 that is disposed between essentially normal wall portions 24 and25. In this case, the irregular wall portion 23 includes a flap 23' thatcan develop due to the weakening and/or stretching of the walls inotherwise normal wall 22. Such flaps frequently result either naturallyor from, for example, stretching by dilation of the vessel duringballoon angioplasty.

Blood 26 flows in a direction represented by arrow 27 within the vessel20. If left untreated, the flap 23' can grow in size and occlude thevessel due to coagulation of blood thereat. Such flaps may also resultin ruptures of the vessel. Other abnormalities in vessels of the type towhich the present invention is applicable include aneurysms, ruptures,stenosis, and the like.

FIGS. 2 and 3 depict a delivery system 28 in accordance with thisinvention that includes a medical catheter 30 extending over apredisposed guidewire 31 generally along an axis 32. The catheter 30includes a proximal end portion (not shown) and a distal end portion 34.The distal end portion supports an expansible balloon 35 with anexpandable stent 36 carried in a constricted or compacted condition onthe balloon. A plurality of lumens in the catheter 30 include aguidewire lumen 37 through which the guidewire 31 extends and aninflation lumen 38 connecting the balloon 35 with a inflation source 39for selectively inflation and deflation.

The stent 36 depicted in FIGS. 2, 4 and 5 includes pores or apertures 40for promoting tissue ingrowth as well as enabling flow to or frombranches of the vessel connecting thereat. Those skilled in the art-willrecognize, however, such pores may in various procedures be unnecessaryor, even, counterproductive. The stent 36 may also be formed of abioabsorbable material, as well as, other known stent constructions(e.g., interlocking loops or mesh formed by filaments, etc.) andmaterials such as various plastic or metals, including tantalum,stainless steel or nitinol wire. Additionally, the stent may also beformed as a graft-carrier, such as an aortic aneurysm graft, as is knownin the art.

FIG. 4 depicts the apparatus 28 after the inflation source 39 expandsthe balloon 35 toward the wall 22 of the vessel 20. Expansion of theballoon urges the stent 36 into an expanded, deployed condition so thatit spans the irregular wall portion 23 and contacts both the adjacentnormal wall portions 24 and 25. Inflation of the balloon 35 in this caseoccludes the vessel 20 and defines a portion or volume 41 of the vesselthat is proximal the balloon 35, the stent 36 and the irregular wallportion 23. Thus, in this embodiment the balloon is part of both balloonmeans associated with the catheter for selective inflating to contactthe walls of the vessel and means associated with the catheter forenabling the deployment of the stent in its expanded form.

Referring again to FIGS. 2 and 3, the catheter 30 has a port 42positioned proximally of the balloon 35. A therapeutic agent source 43and the port are connected by lumen 44 to inject a therapeutic agent 45into the volume 41. In this case, the port 42 and lumen 44 comprisemeans associated with the catheter for delivering a therapeutic agentproximal the inflated balloon and proximate the afflicted wall portionsso that the agent contacts the stent in its expanded form.

The therapeutic agent 45 includes an active agent, such as a drug orendothelial cells. Examples of the drugs which would be appropriateactive agents include antithrombins such as heparin and derivativesthereof; antiplatelet agents such as PPACK, iloprost, integrelin, andchimeric antibodies such as c7E3; genetic therapies including antisenseoligonucleotides and various gene constructs; antipoliferatives such asangiopeptin; chemotherapeutic agents; antioxidants such as probucol;vasorelaxants such as nitroglycerin and papavarin or ones with multipleeffects such as nitric oxide; and the like. The active agent wouldpreferably have an affinity for the afflicted tissue, the stent 35, orboth, or the active agent could be encapsulated or attached to albumin,cells, fibrin and other matrix proteins, platelets, various natural andsynthetic polymers, liposomes, red blood cells or the like having suchan affinity if desired. In such case, the active agent, whether directlyor due to its encapsulation, would attach on or near the irregular wallportion 23. Moreover, encapsulating the active agent in a dissolvingmaterial, such as albumin or various polymers which would effect acontinuing release of the active agent proximate the irregular wallportion 23 during the patency of the encapsulating agent. Examples ofsuch polymers would include pluronics gels, citric acid cycle polymers,such as polylactic acid, polyglycolic acid and derivatives thereof,polyanhydrides, polyphosphazenes, polysaccarides, such as alginic acid,chitin and derivatives thereof, collagen and derivatives thereof, andglycosaminoglycans such as hyaluronis acid and derivatives thereof.

Use of the present invention to treat irregularities in vessel wallsgenerally comprises several stages of treatment. The steps usuallyinclude percutaneously inserting the guidewire 31 into a patient'svessel, guiding the guidewire to a position proximate the irregularityin the vessel 20, and inserting the guidewire lumen 37 of the catheter30 over the guidewire 31 to enable the catheter to be directed to theirregularity, as represent in FIG. 2. Once the catheter 30 is positionedproximate the irregularity, the guidewire may be removed or otherwiseremain.

Inflating the balloon 35 to contact the wall 22 substantially occludesthe vessel 20 and inhibits blood flow therethrough, as depicted in FIG.4. Inflation of the balloon 35 also urges the stent 36 from itscompacted condition to its expanded, operative condition spanning theafflicted wall portion 23 and contacting the adjacent normal wallportions 24 and 25. In this case, the deployed stent 36 holds the flap23' (see FIG. 2) proximate the wall of the vessel 20. With the vesseloccluded, as depicted in FIG. 4, therapeutic agent 45 from the source 43(FIG. 3) enters the volume 41 proximally of the balloon 35 and the stent36 at the port 42.

Deflation of the balloon 35, as depicted in FIG. 5, enables thetherapeutic agent 45 to contact the stent 36 and afflicted wall portion23 through the pores 40 and enables retraction of an extreme distal end47 of the catheter through the stent and ultimately from the patient.After the deployment of the stent 36 and deflation of the balloon 35,the catheter 34 may be moved within the vessel to other sites for eitheror both therapeutic agent and balloon therapy. That is, thereafter theballoon 35 serves as a standard inflatable, catheter-mounted balloonwith the port 42 also providing delivery of therapeutic agents asdesired.

FIGS. 6 and 7 depict another embodiment of this invention as applied tothe vessel 20 with an irregular wall portion 123 comprising an abnormalnarrowing of the vessel or stenosis 123'. A delivery system 128 includesa catheter 130 having a distal portion 134. The catheter 130 carries theballoon 35 with the stent 36 for deployment within the vessel. Theportion 134 also carries an inflatable balloon 137, which in thisinstance is positioned distally of the balloon 35, for occluding orsubstantially occluding the vessel. In some cases a second balloon 137'depicted in phantom lines may be positioned opposite the balloon 35 withrespect to the first balloon 137 or even be used in place of the balloon137.

Referring to FIGS. 6, 7 and 8, a second inflation source 138 inflatesthe balloon 137 into contact with the vessel wall 22 by urging inflatingfluid along a lumen 139. The inflated balloon 137 defines a volume 141in the vessel 20 proximally of the balloon 127 which includes the wallportion 123. Use of the balloon 137' would isolate the volume 141 aboutthe wall portion 123 in which the stent 36 would be positioned. Thetherapeutic agent 45 enters the volume 141 through the port 42proximally adjacent the balloon 35. As previously discussed with respectto FIGS. 4 and 5, the therapeutic agent 45 preferably has an affinityfor either or both the afflicted tissue and the stent 36.

Referring to FIGS. 8 and 9 inflation of the balloon 35 urges the stent36 from its compacted condition. The deployed, expanded stent 36 spansthe afflicted wall portion 123 and contacts the adjacent normal wallportions 24 and 25 to urge the stenotic portion 123' into asubstantially normal position indicated as wall portion 123".Introduction of the therapeutic agent 45 can occur prior to stentdeployment, during stent deployment or after stent deployment, and theballoon 35 may be reinflated to aid disposition of the agent along thestent 36 and wall 123. Deflation of the balloons 137 and 35, as depictedin FIG. 10, enables retraction of the catheter 130 from the patientwhile the stent 36 remains at the repaired wall portion 123".

This embodiment has been described in terms of a four-lumen catheter,although it will be appreciated that various modifications can be made.For example, the balloons 35 and 137 can be inflated from a commonsource through a common lumen when independent inflation is not needed.Those skilled in the art will recognize that this embodiment can also beemployed as a common angioplastic catheter for treating, for example,stenotic irregularities by dilation of the vessel proximate thestenosis.

Specifically, the balloon 137 enables the dilation of vessels to dilatea stenotic vessel in a known manner, as well as other therapiesinvolving either or both balloon and therapeutic agent therapies.However, in situations in which an irregularity of the type adapted fortreatment by stent therapy, such as a flap, rupture or otherirregularity that results from the balloon therapy or is detected duringsuch therapy, in which such irregularity is detected during the balloontherapy, the present invention enables stent and therapeutic agenttherapy without exchanging catheters or other delay. In a such case, thecatheter would be repositioned so as to enable the stent to be deployedat the irregular wall portion and the steps previously described wouldoccur. Thus, this embodiment with a separate inflation balloon 137permits a physician to provide balloon therapies, while also providingstent and therapeutic agent therapy as needed.

In FIGS. 11 and 12 the vessel 20 includes an aneurysmal wall portion 223with a delivery system 228 for providing therapy for aneurysmspositioned proximate thereto. The system 228 includes a catheter 230having a deployment balloon 235 on which a stent 36 is carried fordeployment.

As depicted in FIGS. 12 and 13, a vacuum source 231 connected throughlumen 232 to port 233 evacuates the isolated volume 141 defined betweeninflated balloons 137 and 137'. Evacuation of the volume tends to drawthe blood 26 from the volume 141 and the aneurysmal wall portion 223toward the catheter 230 proximate the original position of the portionin line with the wall portions 24 and 25, as represented by the portion223'. The therapeutic agent source injects the therapeutic agent 45 intothe volume 141 usually after evacuation, although it may also followstent deployment.

Referring to FIGS. 12 and 14, ionizable fluid 234 directed from theinflation source 39 along lumen 38 inflates the balloon 235 to contactthe vessel wall 22 and deploy the stent 35 which may be a standard stentor graft carrying stent. Conductors 251 carried in the lumen 38 connectan rf heating source 252 with spaced electrodes 253 and 254 on thecatheter 230 internally of the balloon. The heating source 252 energizesthe electrodes 253 and 254 with the resulting current between theelectrodes 253 and 254 heating the liquid 234 within the balloon 235,the stent 35 and the surrounding tissue including the weakenedaneurysmal wall 223.

This heat thermally coagulates the weakened aneurysmal wall 223.Specifically, thermal coagulation has the chronic effect of formingfibrous scar tissue in the weakened aneurysmal wall 223. This shrinksand thickens the aneurysmal wall 223 to reduce its compliance and arrestprogression of the aneurysm formation which is further strengthened bythe deployed stent 35. Preferable, a temperature sensor 255 connectedthrough the conductors 251 to the rf heating source 252 provides afeedback control signal to accurately regulate the temperature of theliquid 48.

Upon completion of the treatment with the rf heating source 252deenergized, the vacuum source 45 turned off, and the balloons 137 and235 deflated, the delivery system 228 assumes the compact configurationdepicted in FIG. 15. The blood 26 resumes flow in the direction 127 andthe therapeutic agent 45 not adhering to the stent or wall 123' flowswith the blood. Next a surgeon removes the apparatus 230 leaving thevessel 20 with a thickened and strengthened wall portion 223' with astent 36 in place of the aneurysmal wall 223 of FIG. 13.

Stating that those skilled in the art will now appreciate that both withand without the rf heating the embodiment of FIGS. 11 through 15 enablea therapeutic agent to be administered and then be withdrawn using thevacuum source 45. For example, this can be particularly useful in caseswhere the therapeutic agent has particular toxic or other adverse effecton certain tissues of the body. Thus the physician can apply the drug tothe affected area and then remove it to minimize any adverse impact fromthe therapeutic agent. In a case of an aortic aneurysm after evacuation,the physician can infuse a matrix protein or collagen to coat the graftfor cell adherence in the wall of the graft. The vacuum is then used tosuck out the free material. Thereafter, endothelial cells, which may begenetically altered are infused. These cells then bond to the proteinmatrix which preferably promotes cell growth and division of the infusedendothelial cells.

The specific apparatus 228 in FIGS. 11 through 15 includes a catheter230 with five discrete lumens. Certain functions of these lumens may becombined in a single lumen. For example, the vacuum source 231 andtherapeutic agent source might connect directly to one lumen 44 by meansof a valve 260. In addition, each of the individual components includingthe balloons 137 and the balloon 235 have conventional constructions.Apparatus for heating the liquid 234 in the balloon 235 through the useof rf energy applied to electrodes 253 and 254 and related systemsincluding the temperature sensor 255 are also known in the art.

As depicted in FIG. 16, a balloon for deploying the stent need not fullyocclude a vessel 20 and may be combined with the means for deliveringthe therapeutic agent. Here, a balloon 35' mounted on the catheter 30 inthe vessel 20 comprises an inner impermeable layer or surface 300 and anapertured or otherwise porous layer or outer surface 310 (e.g., achanneled balloon). Lumens (not shown), such as lumen 38 and 44 of FIG.3, have ports between the catheter 30 and the inner surface 300 and thesurface 310, respectively. Through these lumens, the inflation fluidexpands the surface 300 and the therapeutic agent 45 is deliveredinteriorly of the outer surface 310. As previously discussed, the stent36 may be mounted on an expansible balloon, which in this instance isthe balloon 35', for deployment.

Continuing to refer to FIG. 16, the inflation lumen delivers theinflation fluid interiorly of surface 300 to inflate the balloon towardthe walls of a vessel in which the balloon is disposed and to expand astent mounted thereon. The delivery lumen delivers the therapeutic agentintermediate the surfaces 300 and 310. Thus, the therapeutic agent 45exits the balloon 35' through the apertures of the surface 310 tocontact the stent 36 proximate thereto. It will be recognized that theapertured surface 310 comprises a port for the delivery of thetherapeutic agent proximate the stent. Additionally, the apertures inthe surface 310 may be concentrated or entirely positioned in one areaof the balloon 35'. Particularly, the apertures may be provided at theend of the balloon 35' closest the proximal end of the catheter.

Those skilled in the art will appreciate that, as discussed with respectto the embodiment of FIGS. 6 through 10, a second independent inflationballoon may be formed on the catheter 30 of FIG. 16 to provide a secondmeans for dilating the vessel thereby. Additionally, the heating meansof the embodiment of FIGS. 11 through 15 may also be included in eitherof such balloons, as appropriate for the application.

The means for expanding and deploying the stent the invention caninclude the stent itself. For example, certain stents react to heat orother conditions by expanding and deploying. Other stents expand anddeploy upon release of a stent from removable sleeves. The apparatusshown in connection with the various figures is adapted for deployingsuch self-expanding stents. A removable sheath is disposed over thestent to protect the vessel and permit selective deployment of thestent. Employing such self-expanding stents eliminates the requirementfor balloon expansion. However, the balloon still functions to occludethe vessel. Alternatively, as shown in FIGS. 11 through 15, thedeployment balloon 35 of FIGS. 2 and 6, for example, can be providedwith electrodes to heat a heat expansible stent to deploy the stent.

In summary, a delivery system according to each of the embodiments ofthis invention comprises a catheter having means for deploying anexpandable stent and delivering a therapeutic agent for contacting thestent. Moreover, the operating techniques are analogous to standardmedical procedures with respect to positioning the catheters in bloodvessels, inflating the balloons, deploying the stents, and injectingtherapeutic agents so the use of this apparatus is readily mastered.However, the apparatus eliminates the need for repetitive insertion ofapparatus for different treatment modalities and reduces the risk ofadditional trauma to the patient. The invention also improves thetreatment of patients by allowing combined modalities of treatmentrelatively concurrently, as well as successively. The invention alsoincreases the efficiency of doctors, staff, and medical facilities.Moreover, by using bioabsorbable stents no foreign objects, such asclips or tubes, permanently remain permanently in the patient aftertreatment. The invention also provides delivery systems sized for thetreatment of irregularities in both large and relatively small vessels.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:
 1. A catheter assembly for dispensing a stent andadministering a therapeutic agent in a patient's vessel, said catheterassembly comprising:A. elongated flexible tube means including lumenstherein, said flexible tube means having a distal end portion fordelivering a stent positioned distally on said flexible tube means tothe site of the irregularity in the vessel and a proximal end portionfor controlling said distal end portion through said lumens; B.expansible means at said distal end portion for being extended andretracted responsive to manipulation at said proximal end portionthrough one of said lumens, the extension of said expansible meanscausing a deployment of the stent; and C. delivery means associated withsaid flexible tube means for delivering a therapeutic agent proximatethe stent and adjacent portions of the vessel responsive to manipulationof said proximal end portion.
 2. An assembly as recited in claim 1further comprising a balloon means carried by said flexible tube meansat a location that is spaced from said expansible means for limiting theopening in the vessel upon inflation of said balloon means.
 3. Anassembly as recited in claim 2 further comprising second balloon meanscarried by said flexible tube means oppositely spaced from saidexpansible means relative to said first balloon means for limiting theopening in the vessel upon inflation of said second balloon means.
 4. Anassembly as recited in claim 1 further including vacuum port in saiddistal end portion for selectively evacuating fluid proximate saidexpansible means.
 5. An assembly as recited in claim 4 furthercomprising a balloon means carried by said flexible tube means at alocation that is spaced from said expansible means for limiting theopening in the vessel upon inflation of said balloon means.
 6. Anassembly as recited in claim 5 wherein said lumens include an inflationlumen for inflating and deflating said balloon means.
 7. An assembly asrecited in claim 5 further comprising second balloon means carried bysaid flexible tube means oppositely spaced from said expansible meansrelative to said first balloon means for limiting the opening in thevessel upon inflation of said second balloon means.
 8. An assembly asrecited in claim 7 wherein said lumens include at least one inflationlumen for inflating and deflating said first and second balloon means.9. An assembly as recited in claim 4 further comprising a vacuum sourcewherein said lumens include an evacuation lumen connecting said vacuumsource with said vacuum port to enable evacuation of fluid in the vesselproximate the stent.
 10. An assembly as recited in claim 9 wherein saiddelivery means includes said vacuum port and evacuation lumen and asource means for selectively delivering the therapeutic agent throughsaid vacuum port proximate the stent.
 11. An assembly as recited inclaim 1 wherein said delivery means includes source means for providingthe therapeutic agent proximate the stent.
 12. An assembly as recited in11 wherein said therapeutic agent comprises an antithrombin agent. 13.An assembly as recited in claim 11 wherein said therapeutic agentcomprises an antiplatelet therapeutic agent.
 14. An assembly as recitedin claim 11 wherein said therapeutic agent comprises a genetic agent.15. An assembly as recited in claim 11 wherein said therapeutic agentincludes an antiproliferative agent.
 16. An assembly as recited in claim11 wherein said therapeutic agent includes a chemotherapeutic agent. 17.An assembly as recited in claim 11 wherein said therapeutic agentincludes an antioxidant agent.
 18. An assembly as recited in claim 11wherein said therapeutic agent comprises a vasorelaxant agent.
 19. Anassembly as recited in claim 11 wherein said therapeutic agent is a drugwith multiple effects.
 20. An assembly as recited in claim 19 whereinsaid drug comprises nitric oxide.
 21. An assembly as recited in claim 11wherein said therapeutic agent comprises an active agent and carriermeans for attaching proximate the irregularity in the vessel.
 22. Anassembly as recited in claim 21 wherein said carrier means includespolymers.
 23. An assembly as recited in claim 21 wherein said carriermeans encapsulates said active agent.
 24. An assembly as recited inclaim 21 wherein said carrier means attaches to the stent.
 25. A methodfor treating an irregularity in a vessel wall adjacent normal wallportions by disposing a stent in contact with the vessel wall, the stentbeing carried at a distal end of a catheter and said method comprisingthe steps of:A. positioning the distal end of the catheter proximate thevessel wall irregularity from a proximal end of the catheter; B.expanding the stent carried by the catheter to span the irregularity andcontact the adjacent normal wall portions; C. inflating a balloon formedas part of the catheter proximate the distal end of the catheter toexpand the balloon proximate the vessel walls to limit the flow ofbodily fluid through the vessel past the stent; and D. introducing fromthe proximal end of the catheter a therapeutic agent for contacting thevessel proximate the irregular wall portion and the stent.
 26. A methodfor treating an irregularity in the wall of a vessel as recited in claim25 further comprising defining an isolated volume in the vesselextending at least proximally of the stent and evacuating at least aportion of fluid the isolated volume.
 27. A method for treating anirregularity in the wall of a vessel as recited in claim 26 furthercomprising deflating the balloon to enable unobstructed flow of thebodily fluid through the vessel and enable withdrawal of the distal endof the catheter through the deployed stent, wherein said step ofdelivering the therapeutic agent delivers the therapeutic agent into theisolated volume.
 28. A method for treating an irregularity in the wallof a vessel as recited in claim 27 further comprising the step ofinflating a second balloon at the distal end of the catheter through asecond inflation lumen in the catheter positioned proximate a stenoticportion of the vessel so as to dilate and open the vessel thereatwherein said steps of inflating the first balloon, deploying the stentand delivering the therapeutic agent treat occur after said step ofinflating said second balloon.
 29. A method for treating an irregularityin the wall of a vessel as recited in claim 27 further comprisinginflating a second balloon spaced from said first balloon at the distalend of the catheter such that the isolated volume defined in the vesselby the first balloon extends between the first and second balloon andincludes the irregular wall portion wherein said step of delivering thetherapeutic agent delivers the therapeutic agent into the isolatedvolume.
 30. A method for treating an irregularity in the wall of avessel as recited in claim 27 wherein the step of evacuating includesremoving portions of the therapeutic agent delivered by said deliverystep from the isolated volume through a vacuum port in the catheterproximate the balloon.